doi:10.1080/10503307.2025.2541707engMartínez-García, LauraSchaeuffele, CarmenPeris-Baquero, ÓscarTorres Alfosea, María ÁngelesOsma, JorgeAcceptability and preliminary effectiveness of the Unified Protocol in blended format in the Spanish public mental health system: Results from a Pilot Randomized Controlled TrialART-2025-145249Objective: This study evaluated the acceptability and preliminary effectiveness of the UP in blended format, combining face-to-face UP sessions with the use of the UP-App, versus Treatment as Usual (TAU) for treating Emotional disorders (ED) in Spanish specialized mental health units. Methods: A total of 76 adults presenting a diagnosis of ED were randomly assigned to UP + APP (n = 40) or TAU (n = 36) and completed self-report questionnaires at baseline, 3 and 6 months after treatment onset. Results: Improvements in both conditions for ODSIS (b = −2.84; T = −2.36), depressed mood (b = −6.85; T = 0.01), and the describing facet of mindfulness were found (b = 4.01; T = 2.31). No significant differences were found between both conditions in terms of treatment outcomes or in the Time∗Condition interaction. However, engagement with the UPApp understood as number of completed UP-App modules was related to improvements in emotion regulation and the acting with awareness facet of mindfulness, especially at 6 months, suggesting a possible time-dependent effect and UPApp modules completed. The UP-App showed good usability at 3 months (76.47) and excellent at 6 months (83.96), but low adherence (7.5% completers). Satisfaction with the treatment was similar in both conditions. Conclusions: This study suggests that the UP + APP may be as effective as TAU for ED in the SNHS. However, high dropout rates and low adherence to the UP-App constrain these results. Future research should explore a modified implementation format of the UP + APP ensuring a greater presence of the therapist, as well as an updated version of the UP-App incorporating feedback from the current study and new functionalities, in an RCT with a larger sample, as well as comparing standard UP vs UP + APP to determine the unique contribution of the UP-App on effectiveness, adherence, and user experience with UP.2025http://zaguan.unizar.es/record/16270110.1080/10503307.2025.2541707http://zaguan.unizar.es/record/162701oai:zaguan.unizar.es:162701info:eu-repo/grantAgreement/ES/DGA/S31-23Rinfo:eu-repo/grantAgreement/ES/ISCIII-FEDER/PI20-00697PSYCHOTHERAPY RESEARCH (2025), [18 pp.]All rights reservedhttp://www.europeana.eu/rights/rr-f/info:eu-repo/semantics/closedAccess